1. Field of the Invention
The invention relates to a novel method of determining corrosion efficacy of various treatment compounds and, more particularly, to a patch test for determining the efficacy of corrosion inhibitors used for metal cans.
2. Description of the Prior Art
Determination of the efficacy of corrosion prevention treatments applied to metal surfaces is of great importance to industry. The use of metal surfaces which have been improperly treated with corrosion prevention coatings lead to short shelf lives of goods fabricated using these metals. Cans containing foodstuffs which are improperly treated for corrosion prevention during the cooking or cooling process corrode, and while this condition does not bring into direct question the quality of the foodstuff contained in the can, goods look unappealing and unappetizing resulting in their removal from store shelves and their eventual destruction.
Current corrosion testing means are time consuming and do not offer a rapid indication of whether or not metal surfaces, including cans, have been properly treated so that they may attain the longest possible shelf life without visible deterioration due to corrosion. Examples of current tests employed to determine the effect of corrosion prevention treatments include the use of corrosion coupons which are exposed to air (or water) for lengthy periods of time and then carefully weighed to determine metal loss, the use of an apparatus such as a Cleveland humidity cabinet which provides high humidity environments for the exposure of treated metal surfaces over long periods of time, and the exposure of samples of the treated goods to the atmosphere.
All of these treatment methods are time consuming and, as a result of the time taken, by the time a defect, or improperly treated specimen is determined, the goods so treated have frequently been shipped to a customer or further processed.